An electrical connection body is produced widely by laminating an electrical component such as a liquid crystal panel or an organic EL panel and another electrical component such as an IC chip or a flexible circuit board through an uncured adhesive layer formed from a curable adhesive composition and then curing the uncured adhesive layer to form a cured adhesive layer. In this case, when heating performed to cure the uncured adhesive layer is excessive, warpage may occur in the electrical connection body, or the electrical components may be damaged. Therefore, a photocationic polymerizable adhesive composition containing a cationic polymerizable compound such as an epoxy compound and a photoacid generator added as a photocationic polymerization initiator has been used as the curable adhesive composition.
However, when a light-shielding portion such as a metal trace is present in any of the electrical components, the uncured adhesive layer is not irradiated sufficiently with light because of the presence of the light-shielding portion, and this causes a problem in that the die shear strength of the joint portion becomes low. One proposal to address this problem is to add a thermal-radical polymerizable compound such as an acrylate-based monomer or oligomer and a thermal-radical polymerization initiator such as an organic peroxide to the photocationic polymerizable adhesive composition in order to impart thermal curability thereto (Patent Literature 1).